Balloon catheter system

Abstract

The purpose of this invention is to accurately determine the surface temperature of a balloon. The balloon catheter (15) includes a balloon (25), an outer cylinder shaft (30) connected to the proximal end (25b) of the balloon (25), an inner cylinder shaft (35) extending into the balloon (25) through the outer cylinder shaft (30) and connected to the distal end (25a) of the balloon (25), and a heating element (40) disposed within the balloon (25) for heating the liquid within the balloon (25). A fluid delivery path (LP) communicating with the inside of the balloon (25) is formed between the outer cylinder shaft and the inner cylinder shaft. A temperature sensor (45) is provided at the fluid delivery path (LP).

Description

Technical Field

[0001] This invention relates to balloon catheters and balloon catheter systems. Background Technology

[0002] Catheter ablation therapy is a treatment method that uses a catheter inserted into the body to ablate a target site. For example, by ablating and destroying the target site, treatment can be performed for arrhythmias caused by atrial fibrillation, endometritis, cancer, and other diseases. As for catheters used in catheter ablation therapy, balloon catheters with a distal balloon are known, as disclosed in JP3611799B and JP4747141B.

[0003] When the balloon catheter is inserted into the body, the balloon contracts and extends along the length of the catheter. Then, fluid is introduced into the inserted catheter, causing the balloon to inflate. The fluid inside the balloon is temperature-regulated, thereby allowing control of the balloon's surface temperature. By bringing the balloon, conditioned to a predetermined surface temperature, into contact with a peripheral target site, such as the junction of a vein and the atrium, the peripheral target site can be ablated in a single procedure.

[0004] In balloon catheter treatments, accurately controlling the balloon's surface temperature is crucial. In this regard, balloon catheters disclosed in JP3611799B and JP4747141B incorporate a temperature sensor for measuring the balloon's surface temperature. However, JP3611799B uses a temperature sensor mounted on the inner surface of the balloon. However, it is difficult to stably mount a temperature sensor on the surface of a balloon that has expanded from a contracted state. In this regard, JP4747141B proposes a two-layer balloon structure with a temperature sensor positioned between the layers. However, the actual manufacturing process, including balloon fabrication, the placement of the temperature sensor's heat-sensing element, and the handling of the temperature sensor's wiring, is challenging, and the balloon catheter of JP4747141B is not yet widely adopted. In other words, in conventional balloon catheters, it is difficult to determine the balloon's surface temperature with high precision. Summary of the Invention

[0005] The present invention was made with consideration of the above aspects in mind, and its purpose is to be able to determine the surface temperature of the balloon with high precision.

[0006] The first balloon catheter of the present invention includes a balloon, an outer cylinder shaft, an inner cylinder shaft, a heating element, and a temperature sensor. The outer cylinder shaft is connected to the proximal end of the balloon, and the inner cylinder shaft passes through the outer cylinder shaft and extends into the balloon to be connected to the distal end of the balloon. The heating element is disposed in the balloon for heating the liquid inside the balloon, and the temperature sensor is disposed in a liquid delivery path formed between the outer cylinder shaft and the inner cylinder shaft and communicating with the balloon.

[0007] In the first balloon catheter of the present invention, the length from the distal end of the outer cylinder shaft to the temperature sensor along the length direction may be 5 mm or more and 150 mm or less.

[0008] In the first balloon catheter of the present invention, the temperature sensor may be mounted on the inner cylinder shaft, the inner cylinder shaft may be movable relative to the outer cylinder shaft, and the balloon may be extended when the inner cylinder shaft is moved axially distally relative to the outer cylinder shaft. The temperature sensor is located in the fluid delivery path between the outer cylinder shaft and the inner cylinder shaft.

[0009] In the first balloon catheter of the present invention, the temperature sensor may also be mounted on the outer cylinder shaft.

[0010] In the first balloon catheter of the present invention, the temperature sensor may include a heat-sensing part and a wire connected to the heat-sensing part, the wire being fixed to the inner cylinder shaft or the outer cylinder shaft, and the heat-sensing part being separated from the inner cylinder shaft and the outer cylinder shaft.

[0011] The second balloon catheter of the present invention includes a balloon, an outer cylinder shaft, an inner cylinder shaft, a winding electrode, and a temperature sensor. The outer cylinder shaft is connected to the proximal end of the balloon, and the inner cylinder shaft passes through the outer cylinder shaft and extends into the balloon to be connected to the distal end of the balloon, forming a fluid delivery path communicating with the inside of the balloon between the inner and outer cylinder shafts. The winding electrode is disposed inside the balloon and is energized at a high frequency to apply a high-frequency current to the liquid inside the balloon, thereby heating the liquid. The temperature sensor is disposed at a position where the high-frequency current is shielded.

[0012] The first balloon catheter system of the present invention may also be a control device that includes one of the first and second balloon catheters of the present invention, is electrically connected to the temperature sensor, and adjusts the output of the heating component based on the output of the temperature sensor.

[0013] The second balloon catheter system of the present invention may also be a control device that includes one of the first and second balloon catheters of the present invention, is electrically connected to the temperature sensor, and determines the surface temperature of the balloon based on the output of the temperature sensor.

[0014] In the first and second balloon catheter systems of this invention, the control device may also have a display unit that displays the surface temperature.

[0015] In the first and second balloon catheter systems of the present invention, the control device may first determine the temperature variation of the liquid in the delivery path based on the output of the temperature sensor, and then determine the surface temperature of the balloon based on the temperature variation.

[0016] In the first and second balloon catheter systems of the present invention, the control device may first determine the temperature variation of the liquid in the delivery path based on the output of the temperature sensor, and then determine the maximum value of the temperature variation as the surface temperature of the balloon.

[0017] The first and second balloon catheter systems of the present invention may also include a stirring device, which repeatedly supplies the liquid to the delivery path and discharges it from the delivery path at a constant cycle, and the control device obtains an output from the temperature sensor at intervals less than the constant cycle.

[0018] The third balloon catheter system of the present invention includes a stirring device for repeatedly supplying a predetermined amount of the liquid into the liquid delivery path and discharging it from the liquid delivery path at a constant cycle of one of the first and second balloon catheters of the present invention.

[0019] Alternatively, the balloon catheter systems of the first to third embodiments of the present invention may also include a stirring device, which repeatedly supplies a predetermined amount of the liquid to and from the delivery path. The length (mm) from the distal end of the outer cylinder shaft to the temperature sensor along the longitudinal direction is the predetermined amount (mm) of the liquid. 3 Divide by the cross-sectional area of ​​the above-mentioned liquid delivery path (mm²) 2 The values ​​obtained are as follows.

[0020] Alternatively, in the balloon catheter systems of the first to third of the present invention, wiring is provided that is electrically connected to the heating component and the control device, the temperature sensor includes a wire electrically connected to the control device, the inner cylinder shaft is movable relative to the outer cylinder shaft, and the wiring and the wire are both installed on the same side of the outer cylinder shaft and the inner cylinder shaft and extend in the liquid delivery path.

[0021] According to the present invention, the surface temperature of the balloon can be determined with high precision. Attached Figure Description

[0022] Figure 1 This is a diagram illustrating one embodiment, showing a balloon catheter system and a balloon catheter.

[0023] Figure 2 It is Figure 1 The diagram shows the distal portion of the balloon catheter in the inflated state.

[0024] Figure 3 It is Figure 1 The diagram shows the distal portion of the balloon catheter in the balloon's contracted and extended state.

[0025] Figure 4 It is along Figure 2 A cross-sectional view along line IV-IV.

[0026] Figure 5 It is along Figure 2 A cross-sectional view of the VV line.

[0027] Figure 6 The temperature distribution of the distal portion of the coaxial balloon catheter was obtained through thermofluid analysis using CAE.

[0028] Figure 7 The temperature distribution of the distal portion of the balloon catheter in a non-coaxial state was obtained through thermofluid analysis using CAE.

[0029] Figure 8 This is a diagram showing the distal portion of the balloon catheter, used to illustrate the flow of fluid as it is ejected from the delivery path into the balloon.

[0030] Figure 9 This diagram shows the distal portion of the balloon catheter and illustrates the flow of fluid as fluid is drawn from inside the balloon into the delivery path.

[0031] Figure 10 This is a diagram used to illustrate experimental methods using a balloon catheter system.

[0032] Figure 11 It means Figure 10 A diagram of the distal portion of the balloon catheter.

[0033] Figure 12 It means Figure 10 A diagram of the distal portion of a balloon catheter in a coaxial configuration during an experiment.

[0034] Figure 13 It means Figure 10 A diagram of the distal portion of a balloon catheter in a non-coaxial state during an experiment.

[0035] Figure 14 It means Figure 10 The graph shows the measured values ​​of the temperature sensor and the surface temperature sensor obtained from the experiment (liquid volume: 10 ml, contrast agent dilution rate: 1:2, coaxial state).

[0036] Figure 15 It means Figure 10 The graph shows the measured values ​​of the temperature sensor and the surface temperature sensor obtained from the experiment (liquid volume: 10 ml, contrast agent dilution rate: 1:2, non-coaxial state).

[0037] Figure 16 It means Figure 10The graph shows the measured values ​​of the temperature sensor and the surface temperature sensor obtained from the experiment (liquid volume: 10 ml, contrast agent dilution rate: 1:3, coaxial state).

[0038] Figure 17 It means Figure 10 The graph shows the measured values ​​of the temperature sensor and the surface temperature sensor obtained from the experiment (liquid volume: 10 ml, contrast agent dilution rate: 1:3, non-coaxial state).

[0039] Figure 18 It means Figure 10 The graph shows the measured values ​​of the temperature sensor and the surface temperature sensor obtained from the experiment (liquid volume: 20 ml, contrast agent dilution rate: 1:3, coaxial state).

[0040] Figure 19 It means Figure 10 The graph shows the measured values ​​of the temperature sensor and the surface temperature sensor obtained from the experiment (liquid volume: 20 ml, contrast agent dilution rate: 1:3, non-coaxial state).

[0041] Figure 20 It means Figure 10 The graph shows the measured values ​​of the temperature sensor and the surface temperature sensor obtained from the experiment (liquid volume: 20 ml, contrast agent dilution rate: 1:2, coaxial state).

[0042] Figure 21 It means Figure 10 The graph shows the measured values ​​of the temperature sensor and the surface temperature sensor obtained from the experiment (liquid volume: 20 ml, contrast agent dilution rate: 1:2, non-coaxial state).

[0043] Figure 22 This is a diagram showing the balloon catheter system used in the first specific example.

[0044] Figure 23 yes Figure 22 A circuit diagram of the control device used in a balloon catheter system.

[0045] Figure 24 It means according to Figure 23 A flowchart illustrating a method for determining the surface temperature of a balloon based on the detection results of a temperature sensor in a control device.

[0046] Figure 25 This indicates that it will be used Figure 22 The balloon catheter system uses a balloon surface temperature set to 66°C based on the detection results of the temperature sensor. The chart shows the measured values ​​of the temperature sensor and the surface temperature sensor in the experiment.

[0047] Figure 26This is a diagram showing the balloon catheter system used in the second specific example.

[0048] Figure 27 This is a flowchart illustrating a method for determining the surface temperature of a balloon based on the detection results of the temperature sensor in the fourth specific example. Detailed Implementation

[0049] Hereinafter, an embodiment of the present invention will be described with reference to specific examples shown in the accompanying drawings. Furthermore, in the accompanying drawings, for ease of illustration and understanding, the scale and aspect ratios have been appropriately exaggerated from the actual scale and aspect ratios. In addition, the terms used in this specification regarding shape, geometric conditions, and the degrees to which they are defined, such as "parallel," "orthogonal," and "identical," as well as the values ​​of length and angles, are not limited to a strict meaning but are interpreted to include a range of degrees to which the same function can be expected.

[0050] Figure 1 The balloon catheter system 10 shown includes a balloon catheter 15, a control device 70 connected to the balloon catheter 15, and a stirring device 75. Furthermore, the balloon catheter 15 has a catheter body 20 and a handle 50 connected to the proximal end of the catheter body 20, the catheter body 20 having a length direction LD.

[0051] like Figure 2 As shown, the catheter body 20 of this embodiment includes a balloon 25, an outer cylinder 30 connected to the proximal end 25b of the balloon 25, an inner cylinder 35 connected to the distal end 25a of the balloon 25, and a heating element 40 disposed within the balloon 25. The inner cylinder 35 extends into the balloon 25 through the outer cylinder 30. A fluid delivery path LP communicating with the inside of the balloon 25 is formed between the outer cylinder 30 and the inner cylinder 35. The heating element 40 heats the liquid inside the balloon 25.

[0052] In particular, the catheter body 20 (balloon catheter 15) of this embodiment is designed to accurately determine the surface temperature of the balloon 25 filled with heated liquid. Specifically, a temperature sensor 45 disposed at the liquid delivery path LP obtains information about the temperature within the liquid delivery path LP, and the surface temperature of the balloon 25 can be accurately detected based on this information.

[0053] Furthermore, the longitudinal direction LD of the catheter body 20 is defined as the direction in which the central axis of the outer tube shaft 30 and the inner tube shaft 35 extending from the outer tube shaft 30 extends. Additionally, in this specification, the term "distal" as used for each structure of the balloon catheter 15 and the catheter body 20 means the side along the longitudinal direction LD of the catheter body 20 that is away from the handle 50 and the operator (surgeon) of the balloon catheter 15; more specifically, it means the distal side. Furthermore, the term "proximal" as used for each structure of the balloon catheter 15 and the catheter body 20 means the side along the longitudinal direction LD of the catheter body 20 that is close to the handle 50 and the operator (surgeon) of the balloon catheter 15; more specifically, it means the basal side.

[0054] The balloon catheter system 10 and balloon catheter 15 will be described in further detail below. First, the catheter body 20 of the balloon catheter 15 will be described in detail. As described above, the catheter body 20 of the balloon catheter 15 of this embodiment includes a balloon 25, an outer cylinder shaft 30, an inner cylinder shaft 35, a heating element 40, and a temperature sensor 45.

[0055] Both the outer cylinder shaft 30 and the inner cylinder shaft 35 are cylindrical, typically forming a cylindrical shape. Therefore, both the outer cylinder shaft 30 and the inner cylinder shaft 35 have cavities that serve as internal spaces. For example, a guide wire (not shown) is inserted into the cavity formed by the inner cylinder shaft 35. The inner cylinder shaft 35 is inserted into the cavity formed by the outer cylinder shaft 30. That is, the outer cylinder shaft 30 and the inner cylinder shaft 35 have a double-cylinder structure. The inner diameter of the outer cylinder shaft 30 is larger than the outer diameter of the inner cylinder shaft 35. Therefore, the cavity remains between the outer cylinder shaft 30 and the inner cylinder shaft 35. This cavity between the outer cylinder shaft 30 and the inner cylinder shaft 35 forms a liquid delivery path LP. Figure 2 As shown, the fluid delivery path LP communicates with the inside of the balloon 25. Furthermore, the fluid delivery path LP extends into the handle 50.

[0056] The lengths of the outer cylinder shaft 30 and the inner cylinder shaft 35 are preferably 500 mm to 1700 mm, more preferably 600 mm to 1200 mm. The outer cylinder shaft 30 and the inner cylinder shaft 35 are preferably made of a flexible material with excellent antithrombotic properties. Examples of flexible materials with excellent antithrombotic properties include fluoropolymers, polyamides, polyurethane-based polymers, or polyimides, but are not limited to these. Furthermore, to balance sliding with the inner cylinder shaft 35 and adhesion or thermal welding with the balloon 25, the outer cylinder shaft 30 is preferably made by layering different flexible materials.

[0057] The outer diameter of the outer cylinder shaft 30 is preferably 3.0 mm to 4.0 mm. The inner diameter of the outer cylinder shaft 30 is preferably 2.5 mm to 3.5 mm. Furthermore, the outer diameter of the inner cylinder shaft 35 is preferably 1.4 mm to 1.7 mm. The inner diameter of the inner cylinder shaft 35 is preferably 1.1 mm to 1.3 mm.

[0058] Furthermore, the balloon 25 is connected to the outer cylindrical shaft 30 and the inner cylindrical shaft 35. The balloon 25 is formed to inflate upon filling with fluid and to contract upon expelling fluid. Preferably, the balloon 25 has a shape suitable for the target site (e.g., a blood vessel) to be treated. As an example, the shape of the balloon 25 suitable for the pulmonary vein junction of the left atrium can be a spherical shape with a diameter of 15 mm to 40 mm. Here, the spherical shape includes a perfect sphere, an oblate spheroid, and an elongated sphere, and also includes a nearly spherical shape.

[0059] The membrane thickness of the balloon 25 is preferably 10µm to 200µm. Furthermore, the material of the balloon 25 is preferably a stretchable material with excellent antithrombotic properties, specifically a polyurethane-based polymer material. Examples of polyurethane-based polymer materials used in the balloon 25 include thermoplastic polyether polyurethane, polyether polyurethane urea, fluorinated polyether polyurethane urea, polyether polyurethane urea resin, or polyether polyurethane urea amide.

[0060] In the catheter body 20 shown in the figure, as Figure 2 and Figure 3 As shown, the distal end (terminus) 25a of the balloon 25 is fixed to the distal end (terminus) 35a of the inner cylinder shaft 35, and the proximal end (base end) 25b of the balloon 25 is fixed to the distal end (terminus) 30a of the outer cylinder shaft 30. The connection between the balloon 25 and the outer cylinder shaft 30 and the inner cylinder shaft 35 can be achieved using a joint based on adhesive bonding or thermal welding.

[0061] The outer cylinder shaft 30 and the inner cylinder shaft 35 move relative to each other along the length direction LD, thereby deforming the balloon 25 connected to the outer cylinder shaft 30 and the inner cylinder shaft 35. In the illustrated example, the size of the balloon 25 along the length direction LD can be adjusted by the relative movement of the outer cylinder shaft 30 and the inner cylinder shaft 35. Figure 3 As shown, the inner cylinder shaft 35 moves distally relative to the outer cylinder shaft 30 along the length direction LD, thereby extending the balloon 25 along the length direction LD and thus placing it in a tensile state. In the illustrated example, the range of movement of the inner cylinder shaft 35 distally relative to the outer cylinder shaft 30 along the length direction LD is limited by the balloon 25. The inner cylinder shaft 35 from Figure 3 The balloon 25 is moved proximally relative to the outer cylinder axis 30 along the length direction LD, thus relaxing the balloon. Fluid is introduced into the relaxed balloon 25, thereby... Figure 2 As shown, the balloon 25 can be inflated. That is, the size of the balloon 25 in the length direction LD can be adjusted by the relative movement of the outer cylinder shaft 30 and the inner cylinder shaft 35.

[0062] Next, the heating element 40 will be described. The heating element 40 is disposed within the balloon 25. The heating element 40 is a component used to heat the liquid filling the balloon 25. As an example, the heating element 40 can be a nickel-chromium alloy wire with resistance heating. Other examples of the heating element 40 include... Figure 2 and Figure 3 As shown, a winding electrode 41 can be used. By applying high-frequency current to the heating element 40, which serves as the winding electrode 41, a phase is formed with the externally disposed opposing electrode 77. Figure 1 A high-frequency current flows between the winding electrode 41 and the opposing electrode 77, and the liquid between them generates Joule heat. The opposing electrode 77 is, for example, positioned on the back of the patient.

[0063] exist Figure 2 and Figure 3 In the example shown, the winding electrode 41 is disposed on the inner cylinder shaft 35 extending within the bulb 25. The winding electrode 41 can be constructed from a wire wound around the inner cylinder shaft 35. The winding electrode 41 is electrically connected to the wiring 42 for high-frequency energization. The wiring 42 extends to the handle 50 within the liquid delivery path LP, which serves as the cavity between the outer cylinder shaft 30 and the inner cylinder shaft 35. As a specific example of the winding electrode 41 constituting the heating element 40, a winding electrode constructed by stripping the insulation coating from the wire used for the wiring 42 and winding it around the inner cylinder shaft 35 can be used. Such a winding electrode 41, being integrally constructed with the wiring 42, can effectively suppress the occurrence of defects such as wire breakage.

[0064] The diameter of the winding electrode 41 and the wiring 42 is preferably 0.1 mm to 1 mm, more preferably 0.1 mm to 0.4 mm. Examples of conductive materials constituting the winding electrode 41 and the wiring 42 include copper, silver, gold, platinum, and their alloys. Regarding the wiring 42, to prevent short circuits, it is preferably configured such that the conductive linear portion is covered by an insulating film, for example, using a fluoropolymer (see reference). Figure 4 and Figure 5 ).

[0065] Next, the temperature sensor 45 will be described. The temperature sensor 45 acquires information about the temperature of the liquid. In this embodiment, the temperature sensor 45 has a heat-sensing part 46 disposed within the liquid delivery path LP located between the outer cylinder shaft 30 and the inner cylinder shaft 35. Furthermore, according to the inventors' research, based on the information acquired by this temperature sensor 45, the surface temperature of the balloon 25, which is crucial in ablation therapy using the balloon catheter system 10, can be determined with high precision. By placing the temperature sensor 45 between the outer cylinder shaft 30 and the inner cylinder shaft 35, compared to placing the temperature sensor 45 inside the balloon 25, the manufacture of the catheter body 20 can be significantly simplified. Furthermore, compared to the balloon 25, which has a very thin wall and causes significant deformation during use, by disposing of the temperature sensor 45 between the outer cylinder shaft 30 and the inner cylinder shaft 35, external stress can be protected from the temperature sensor 45, and it can be stably supported. That is, by installing the temperature sensor 45 in the liquid delivery path LP between the outer cylinder shaft 30 and the inner cylinder shaft 35, the quality and reliability of the balloon catheter system 10 and the balloon catheter 15 can be significantly improved.

[0066] In order to accurately determine the surface temperature of the balloon 25, the preferred length DX of the outer cylinder shaft LD along its length direction from the distal end 30a of the outer cylinder shaft 30 to the heat-sensing part 46 of the temperature sensor 45 is strictly dependent on the amount of liquid supplied and discharged by the stirring device 75, as described later. However, considering the various sizes of the balloon catheter 15 commonly used in cardiac ablation therapy and the amount of liquid supplied and discharged from the stirring device 75, the preferred length DX from the distal end 30a of the outer cylinder shaft 30 to the temperature sensor 45 (see reference) is preferred. Figure 2 The value is set to 5mm or more and 150mm or less, more preferably 10mm or more and 20mm or less.

[0067] In addition, unless otherwise specified, the length DX from the distal end 30a of the outer cylinder shaft 30 to the temperature sensor 45 is, Figure 2 The length of the balloon 25 shown is determined when it is inflated due to the liquid. Similarly, unless otherwise specified, the descriptions of temperature sensor 45 being located within the liquid delivery path LP, within the outer cylinder shaft 30, or between the outer and inner cylinder shafts 35 are used to indicate that... Figure 2 The balloon 25 shown is inflated due to the liquid.

[0068] A thermocouple or a thermistor can be used as the temperature sensor 45. Furthermore, a T-type thermocouple is particularly preferred as the temperature sensor 45. With a T-type thermocouple, the heat capacity of the heat-sensing part 46 can be reduced. In addition, by using a T-type thermocouple as the temperature sensor 45, the thermoelectric potential is stabilized. Furthermore, with a T-type thermocouple, the temperature range of 50°C to 80°C can be detected with high precision, making it particularly suitable for cardiac ablation therapy. Additionally, information about the temperature obtained by the temperature sensor 45 includes, for example, the potential obtainable from the thermocouple and the resistance value obtainable from the thermistor.

[0069] like Figure 2 and Figure 3 As shown, the temperature sensor 45 typically includes a heat-sensing part 46 and a wire 47 electrically connected to the heat-sensing part 46. In a temperature sensor 45 that is a thermocouple, the heat-sensing part 46 is the portion connected to a dissimilar metal. In a temperature sensor 45 that is a thermistor, a ceramic element constitutes the heat-sensing part 46. The wire 47 extends to the handle 50 within the liquid delivery path LP, which serves as the cavity between the outer cylinder shaft 30 and the inner cylinder shaft 35.

[0070] The diameter of the wire 47 is preferably 0.05 mm to 0.5 mm, more preferably 0.05 mm to 0.3 mm. In the temperature sensor 45, which functions as a thermocouple, copper can be used for one wire 47 and constantan for the other. In this example, the heat-sensing part 46 formed by joining a pair of wires 47 can function as a T-type thermocouple. To prevent a short circuit between the pair of wires 47, such as... Figure 4 and Figure 5 As shown, a coating with electrical insulation properties, such as a fluoropolymer or enamel, is preferably provided.

[0071] In the illustrated example, temperature sensor 45 is mounted on inner cylinder shaft 35. (As shown...) Figures 2-4 As shown, the wire 47 of the temperature sensor 45 is fixed, thereby mounting the temperature sensor 45 to the inner cylinder shaft 35. Furthermore, the heat-sensing part 46 is separated from both the outer cylinder shaft 30 and the inner cylinder shaft 35. In other words, the heat-sensing part 46 does not contact the outer cylinder shaft 30 or the inner cylinder shaft 35. Therefore, the responsiveness of the temperature sensor 45 can be prevented from deteriorating due to the high heat capacity of the outer cylinder shaft 30 and the inner cylinder shaft 35. Thus, the temperature of the liquid in the liquid delivery path LP can be evaluated with high responsiveness and high accuracy using the temperature sensor 45. Furthermore, the fixing mechanism 48 for fixing the wire 47 to the inner cylinder shaft 35 is not particularly limited, and various mechanisms can be used. In the illustrated example, a heat-shrinkable tube that shrinks upon heating is used as the fixing mechanism 48. However, it is not limited to this example; various shrink tubes, adhesive tapes, adhesives, etc., can be used as the fixing mechanism 48.

[0072] In the illustrated example, wiring 42 is not installed on either the outer cylinder shaft 30 or the inner cylinder shaft 35, but this is not a limitation; wiring 42 may also be installed on either the outer cylinder shaft 30 or the inner cylinder shaft 35. Preferably, both wiring 42 and the wire 47 of the temperature sensor 45 are preferably installed on the same side of the outer cylinder shaft 30 and the inner cylinder shaft 35. According to this specific example, it is possible to effectively prevent wiring 42 and wire 47, which both extend within the liquid delivery path LP, from becoming entangled when the outer cylinder shaft 30 and the inner cylinder shaft 35 move relative to each other. As a result, the liquid temperature inside the balloon based on the heating element 40 can be stably regulated, and the surface temperature of the balloon 25 can be stably controlled.

[0073] In addition, such as Figure 3 As shown, with the inner cylinder shaft 35 maximally moved relative to the outer cylinder shaft 30 distal in the longitudinal direction LD, causing the balloon 25 to extend, the temperature sensor 45 is also located within the outer cylinder shaft 30. According to this specific example, the temperature sensor 45 can be located within the outer cylinder shaft 30 regardless of the relative position of the inner cylinder shaft 35 relative to the outer cylinder shaft 30. Therefore, the temperature sensor 45 can be stably protected by the outer cylinder shaft 30 regardless of the relative position of the inner cylinder shaft 35 relative to the outer cylinder shaft 30.

[0074] Alternatively, unlike the illustrated example, the temperature sensor 45 may be mounted on the outer cylinder shaft 30. For example, the wire 47 of the temperature sensor 45 may also be fixed to the inner surface of the outer cylinder shaft 30. According to this specific example, the temperature sensor 45 is located inside the outer cylinder shaft 30 regardless of the relative position of the inner cylinder shaft 35 relative to the outer cylinder shaft 30. Therefore, the temperature sensor 45 can be stably protected by the outer cylinder shaft 30 regardless of the relative position of the inner cylinder shaft 35 relative to the outer cylinder shaft 30.

[0075] Next, the handle 50, which is connected proximally to the catheter body 20 as described above, will be explained. The handle 50 is the part that the operator (surgeon) holds during the use of the balloon catheter system 10. Therefore, the handle 50 is preferably designed to be easy for the operator to hold and operate. The material constituting the handle 50 is preferably a material with high chemical resistance, for example, polycarbonate or ABS resin can be used.

[0076] Figure 1 The handle 50 shown has a first handle portion 51 and a second handle portion 52 that can slide against each other. The first handle portion (front handle portion) 51 is connected to the outer cylinder shaft 30 of the catheter body 20. The second handle portion (rear handle portion) 52 is connected to the inner cylinder shaft 35 of the catheter body 20. By moving the second handle portion 52 relative to the first handle portion 51, the inner cylinder shaft 35 can be moved relative to the outer cylinder shaft 30.

[0077] like Figure 1As shown, the handle 50 also functions as a connection point for connecting the balloon catheter system 10 and other devices included in the balloon catheter system 10 to the balloon catheter 15.

[0078] First, connector 56 extends from the second handle portion 52. This connector 56 electrically connects the wiring 42 and the wire 47 of the temperature sensor 45 to the external control device 70. Connector 56 extends from one of the plurality of branch portions 52a provided in the second handle portion 52. When the wiring 42 and the wire 47 are connected to the external device (control device 70) via the same handle portion, the wiring 42 and the wire 47 are installed on the same side of the outer cylinder shaft 30 and the inner cylinder shaft 35 as described above, and particularly preferably on the shaft (inner cylinder shaft 35) connected to this handle portion (the second handle portion 52 in the illustrated example). In this case, tangling and breakage of the wiring 42 and the wire 47 can be more effectively avoided.

[0079] The connector 56 is preferably configured to effectively prevent misconnection. Furthermore, the connector 56 preferably has excellent water resistance. The structure of the connector 56 can be determined with consideration for the convenience of the surgeon and design considerations. Additionally, as the material constituting the connector 56, it is preferably, in the same manner as the handle 50, a material with high chemical resistance; for example, polycarbonate or ABS resin is suitable.

[0080] The connector 56 may also have a high-conductivity metal pin internally. The wiring 42 and conductor 47 can be electrically connected to the control device 70, which serves as a high-frequency power supply mechanism, by connecting to this high-conductivity metal pin. However, the conductor 47 can also be electrically connected to devices other than the control device 70, such as a temperature display. The material of the high-conductivity metal pin included in the connector 56 is not particularly limited to any type of high-conductivity metal. Examples of high-conductivity metal pins included in the connector 56 include, for example, copper, silver, gold, platinum, and their alloys. Furthermore, the exterior of the high-conductivity metal pin is preferably protected by an electrically insulating and chemically resistant material. Examples of electrically insulating and chemically resistant materials include, for example, polysulfone, polyurethane polymers, polypropylene, or polyvinyl chloride.

[0081] In addition, the second handle portion 52 has branch portions 52b and 52c, excluding the branch portion 52a connected to the connector 56. These branch portions 52b and 52c function as: portions for supplying liquid to the lumen, which is the internal space of the inner cylinder shaft 35, and portions for the guide wire inserted into the lumen of the inner cylinder shaft 35. During cardiac ablation treatment, generally, about 100 ml of physiological saline solution is sprayed into the body through the lumen of the inner cylinder shaft 35 every hour. By spraying physiological saline solution, the backflow of blood from the inner cylinder shaft 35 into the lumen can be effectively prevented.

[0082] In addition, such as Figure 1 As shown, the extension tube 57 extends from the first handle portion 51. This extension tube 57 connects the liquid delivery path LP of the conduit body 20 to an external supply device 74 or a stirring device 75. The extension tube 57 extends from a branch portion 51a provided at the first handle portion 51. The extension tube 57 is connected to the supply device 74 and the stirring device 75 via a valve 58. In the illustrated example, by operating the valve 58, it is possible to select whether the supply device 74 or the stirring device 75 is connected to the liquid delivery path LP. A three-way stopcock valve can be used as the valve 58.

[0083] Next, the balloon catheter 15 described above and the devices constituting the balloon catheter system 10 will be described, specifically the control device 70, the supply device 74, and the stirring device 75.

[0084] The illustrated control device 70 is electrically connected to the winding electrode 41 via wiring 42. The control device 70 includes a high-frequency energizing control unit 70A that controls the high-frequency energizing toward the winding electrode 41. In the illustrated example, the high-frequency energizing control unit 70A controls the high-frequency energizing to the winding electrode 41, thereby adjusting the output from the heating element 40. Furthermore, the high-frequency energizing control unit 70A can control the high-frequency energizing to the winding electrode 41 based on the surface temperature of the balloon 25 determined by the temperature calculation unit 70B (described later), or through a preset process, or through input from the operator.

[0085] Furthermore, the control device 70 is electrically connected to the wire 47 of the temperature sensor 45. The control device 70 has a temperature calculation unit 70B, which calculates the temperature information obtained from the inner cylinder shaft 35. Based on the temperature information obtained from the temperature sensor 45, the temperature calculation unit 70B calculates the liquid temperature in the liquid delivery path LP, and then estimates the surface temperature of the balloon 25 based on the calculated liquid temperature. The temperature calculation unit 70B can also display the determined surface temperature of the balloon 25 on the display unit 71. The method for determining the surface temperature of the balloon 25 will be described in detail later.

[0086] Furthermore, the control device 70 includes a stirring device control unit 70C for controlling the stirring device 75. The stirring device control unit 70C may also display the control conditions of the stirring device 75 on the display unit 71.

[0087] The heating device 70 may be constructed from hardware such as a CPU. One or more of the high-frequency power control unit 70A, temperature calculation unit 70B, and stirring device control unit 70C included in the heating device 70 may be constructed as separate hardware or as a part thereof. At least a part of the control device 70 may also be constructed from software. A part of the control device 70 may also be physically separated. Furthermore, the control device 70 may be a structural component capable of communicating and cooperating with other structural components via a network. Additionally, the control device 70 may be a device whose structural component can communicate with other structural components via an external network, for example, it may reside on a cloud server or database.

[0088] Next, the supply device 74 will be described. The supply device 74 supplies liquid into the liquid delivery path LP. Liquid is supplied from the supply device 74 to the balloon 25 via the liquid delivery path LP, thereby enabling... Figure 2 The balloon 25 is inflated as shown. Alternatively, the balloon 25 can be deflated by discharging fluid from the supply device 74 through the fluid delivery path LP. The fluid supplied to the fluid delivery path LP is typically physiological saline. A syringe can be used as the supply device 74, as shown. However, a pump or the like can also be used as the supply device 74.

[0089] Next, the stirring device 75 will be described. The stirring device 75 is provided for stirring the liquid inside the spherical bladder 25. By stirring the liquid inside the spherical bladder 25, the heat supplied to the spherical bladder 25 can be dispersed or homogenized, and the surface temperature of the spherical bladder 25 can be adjusted. The stirring device 75 repeatedly supplies liquid to the liquid delivery path LP and discharges liquid from the liquid delivery path LP. As the stirring device 75, a pump selected from a group consisting of a roller pump, diaphragm pump, bellows pump, vane pump, centrifugal pump, piston, and pressure cylinder combination can be used.

[0090] The liquid supply rate to and from the liquid delivery path LP can be set to a constant (e.g., 5 ml to 30 ml). Furthermore, the liquid supply to and from the liquid delivery path LP can be repeated at a constant cycle (e.g., once to five times per second). The liquid supply rate to and from the liquid delivery path LP can also be adjusted based on a control signal from the stirring device control unit 70C or direct input from the operator. Similarly, the cycle of liquid supply to and from the liquid delivery path LP can be adjusted based on a control signal from the stirring device control unit 70C or direct input from the operator.

[0091] Next, an example of how to use the balloon catheter system 10 configured as described above will be explained.

[0092] First, operate valve 58 to connect supply device 74 to the liquid delivery path LP of conduit body 20 via handle 50. Then, operate supply device 74 to allow liquid to flow into liquid delivery path LP, filling balloon 25, liquid delivery path LP, and extension tube 57 with liquid. Next, move inner cylinder shaft 35 relative to outer cylinder shaft 30 towards the distal (end) side in the length direction LD, as... Figure 3 The balloon 25 is extended as shown. At this time, by operating the first handle portion 51 and the second handle portion 52 of the handle 50, the outer cylinder shaft 30 and the inner cylinder shaft 35 can be moved relative to each other. Then, the catheter body 20 with the balloon 25 extended is inserted into the body.

[0093] Guide the distal end of the catheter body 20 toward the target site (affected area), causing the inner tube shaft 35 to move relative to the outer tube shaft 30 proximally (towards the base) along the length direction LD, thus relaxing the balloon 25. Next, operate valve 58, connecting the supply device 74 to the fluid delivery path LP of the catheter body 20 via handle 50. Then, operate the supply device 74 to allow fluid to flow into the fluid delivery path LP, as... Figure 2 As shown, the balloon 25 is inflated by the use of liquid.

[0094] Next, valve 58 is operated to disconnect the supply device 74 from the liquid delivery path LP, connecting the stirring device 75 to the liquid delivery path LP. The stirring device 75 is controlled by a control signal from the stirring device control unit 70C of the stirring control device 70. The stirring device 75 repeatedly performs the supply of a constant amount of liquid to the liquid delivery path LP and the discharge of a constant amount of liquid from the liquid delivery path LP at a constant cycle. Thus, the constant amount of liquid ejected from the liquid delivery path LP into the balloon 25 and the constant amount of liquid drawn from the balloon 25 into the liquid delivery path LP are repeated at a constant cycle, and the liquid inside the balloon 25 is stirred.

[0095] Furthermore, the temperature of the liquid inside the balloon 25 is regulated by controlling the heating element 40 with the high-frequency energization control unit 70A of the control device 70. Specifically, high-frequency energization is applied from the control device 70 between the winding electrode 41 constituting the heating element 40 and the opposing electrode 77 disposed outside the patient's body. As a result, a high-frequency current is generated between the winding electrode 41 and the opposing electrode 77. However, by making the size of the winding electrode 41 significantly smaller than that of the opposing electrode 77, the current density around the winding electrode 41 becomes higher, and the liquid and contrast agent around the winding electrode 41 are heated by Joule heating.

[0096] Additionally, a temperature sensor 45 is positioned near the winding electrode 41. However, the temperature sensor 45 is not located inside the bulb 25, but rather inside the outer cylinder shaft 30, which has a much greater thickness than the bulb 25. Therefore, the temperature sensor 45 is shielded from high-frequency current by the outer cylinder shaft 30. This effectively prevents the temperature sensor 45 and the surrounding liquid from experiencing localized temperature increases due to the influence of high-frequency current. In other words, the temperature sensor 45 effectively prevents the detection of abnormal values.

[0097] The liquid inside the balloon 25 is heated and stirred simultaneously as described above. The balloon 25, containing the heated liquid, is then pushed towards the target area to ablate it. During ablation, a temperature sensor 45 disposed within the liquid delivery path LP acquires information about the liquid temperature within the liquid delivery path LP. This acquired information is processed by the temperature calculation unit 70B of the control device 70. Specifically, the temperature calculation unit 70B not only determines the liquid temperature in the area of ​​the heat-sensing section 46 where the temperature sensor 45 is disposed, but also, as described later, can determine the surface temperature of the balloon 25 with high precision. The surface temperature of the balloon 25, accurately determined by the temperature calculation unit 70B, is displayed, for example, on the display unit 71.

[0098] That is, by using this balloon catheter system 10, the operator can always perform ablation treatment while accurately controlling the surface temperature of the balloon 25. Therefore, the operator can perform the procedure while adjusting the crucial surface temperature of the balloon 25 to the ideal temperature during ablation treatment. As a result, the effectiveness of ablation treatment can be significantly improved.

[0099] When ablation of the target area is complete, the energy supply to the heating element 40 is stopped. Furthermore, the valve 58 is operated, and the supply device 74 is connected to the liquid delivery path LP of the catheter body 20 via the handle 50, while the liquid delivery path LP is cut off from the stirring device 75. Then, liquid is discharged from the liquid delivery path LP using the supply device 74, causing the balloon 25 to contract. Next, the second handle 52 is operated to... Figure 3 The balloon 25, which had been contracted as shown, is extended. Then, the catheter body 20, with the balloon 25 extended, is withdrawn from the body. Based on the above, the procedure using the balloon catheter system 10 is completed.

[0100] Next, in more detail, the temperature sensor 45, which obtains information about the temperature in the liquid delivery path LP by means of a heat-sensing part 46 arranged between the outer cylinder shaft 30 and the inner cylinder shaft 35, can detect the surface temperature of the spherical bag 25 with high precision.

[0101] first, Figure 6 and Figure 7The results are from a simulation of the temperature distribution inside the balloon 25 using CAE (computer aided engineering). Figure 6 The simulation results are under the condition that the LD pushes the sphere 25 toward the target part along the length direction (hereinafter referred to as the "coaxial state"). Figure 6 In the example shown, the outer cylinder shaft 30 is arranged in a roughly straight line relative to the inner cylinder shaft 35 and the heating element 40 within the balloon 25. On the other hand, Figure 7 The simulation results are under the condition that the balloon 25 is pushed towards the target part from the direction of inclination relative to the length direction LD (hereinafter referred to as "non-coaxial state"). Figure 7 In the example shown, the outer cylinder shaft 30 is tilted significantly relative to the inner cylinder shaft 35 and heating element 40 within the balloon 25.

[0102] According to the simulation results, even when the liquid inside the balloon 25 is stirred using the stirring device 75, a temperature gradient is still generated in the liquid inside the balloon 25 due to the configuration of the heating element 40. When the winding electrode 41 is used as the heating element 40, this temperature distribution exhibits the same tendency as the current density distribution. The temperature distribution inside the balloon 25 is... Figure 6 In the coaxial configuration shown, temperatures above 5°C are generated. Figure 7 The non-coaxial state shown generates approximately 5°C. Because the balloon 25 is pushed towards the target area, the temperature distribution within the balloon 25 also changes. Therefore, it is considered difficult to determine the surface temperature of the balloon 25 based solely on information from a temperature sensor positioned near the heating element 40 within the balloon 25.

[0103] On the other hand, the temperature of the liquid in the region near the distal end 30a within the outer cylinder shaft 30, where the temperature sensor 45 is configured, is... Figure 6 The coaxial state shown and Figure 7 In the non-coaxial states shown, the temperature is different from the liquid temperature around the heating element 40, but approximately the same as the surface temperature of the balloon 25. Firstly, this can be understood as follows: by placing the heat-sensing part 46 of the temperature sensor 45 between the outer cylinder shaft 30 and the inner cylinder shaft 35, the surface temperature of the balloon 25 can be detected with high precision.

[0104] Furthermore, the temperature gradient centered on the heating element 40 within the balloon 25 occurs not only at the heating element 40 where resistance heating based on nickel-chromium alloy wire is expected, but also, as confirmed by simulation results, at the heating element 40 with the high-frequency energized winding electrode 41. When the winding electrode 41 and the external opposing electrode 77 are energized at high frequency, a high-frequency current flows between the winding electrode 41 and the opposing electrode 77. The high-frequency current has a high resistivity in the liquid near the winding electrode 41, thus causing the high-frequency current to flow between the winding electrode 41 and the opposing electrode 77.

[0105] (Value of the flowing current) 2 ×(resistance value of the filling fluid)

[0106] The Joule heat is generated in a concentrated manner. This Joule heat decreases rapidly as it leaves the winding electrode 41. This is because, "(the value of the flowing current)..." 2 The term "(resistance of the filling fluid)" in "(current value of the flowing fluid)" decreases with the square of the distance. For example, Figure 6 The simulation results show that when the liquid temperature near the heating component 40 is 70 degrees, the surface temperature of the balloon drops to below 65 degrees.

[0107] Next, the effect of stirring by the stirring device 75, which repeatedly supplies and discharges liquid, on the temperature of the liquid was also studied and experimented on. The following describes the research and experiments conducted by the inventors of this application.

[0108] When liquid is supplied from the stirring device 75 to the liquid delivery path LP, such as Figure 8 As shown, liquid is ejected into the balloon 25 from the distal end 30a of the outer cylinder shaft 30. This agitates the liquid inside the balloon 25, causing the relatively hot liquid around the heating element 40 to move to the surface of the balloon 25. Specifically, in the illustrated example, the distal end 30a of the outer cylinder shaft 30 opens into the heating element 40. Therefore, liquid is ejected from the distal end 30a of the outer cylinder shaft 30 into the heating element 40. This allows heat around the heating element 40 to diffuse efficiently into the balloon 25.

[0109] On the other hand, when the stirring device 75 discharges liquid from the liquid delivery path LP, such as Figure 9 As shown, liquid inside the balloon 25 is drawn into the outer cylinder shaft 30. At this time, the hot liquid inside the balloon 25 flows into the liquid delivery path LP. In particular, the inventors of this application have conducted in-depth research and, when liquid is immediately ejected from the outer cylinder shaft 30 into the heating element 40 at the center of the balloon 25, or when liquid is drawn into the liquid delivery path LP from the generally spherical balloon 25 in parallel with the ejection, and when the heating element 40 is located at the center of the generally spherical balloon 25, it has been confirmed that liquid flowing along the surface of the balloon 25 tends to flow into the liquid delivery path LP. Therefore, according to this embodiment, by measuring the temperature of the liquid flowing into the liquid delivery path LP, the surface temperature of the balloon 25 can be determined with high accuracy.

[0110] Furthermore, from this perspective, the heat-sensing part 46 of the temperature sensor 45 is preferably located near the distal end 30a of the outer cylinder shaft 30. More specifically, it is preferably located in the region of the liquid drawn into the bladder 25 during liquid aspiration by the stirring device 75 in the liquid delivery path LP near the distal end 30a of the outer cylinder shaft 30. Thus, the temperature of the liquid located immediately in front of the surface of the bladder 25 within the outer cylinder shaft 30 can be detected by the temperature sensor 45. Specifically, preferably, the length DX from the distal end 30a of the outer cylinder shaft 30 to the temperature sensor 45 (refer to...) Figure 2 ) is set to the liquid discharge rate (mm) from the liquid delivery path LP based on the stirring device 75. 3 Divide by the cross-sectional area of ​​the liquid delivery path LP (mm²) 2 The values ​​obtained are as follows.

[0111] Furthermore, if based on Figure 8 and Figure 9 The study shown anticipates that the temperature of the liquid detected by temperature sensor 45 is within the range of... Figure 8 The state of liquid being ejected into the balloon 25 is shown. Figure 9 The conditions shown are different from those in which liquid is drawn from the balloon 25. Specifically, in Figure 8 In the indicated state, the temperature of the liquid that is not heated by the heating element 40 located closer to the temperature sensor 45 is measured, thus detecting a lower temperature. On the other hand, in Figure 9 In the state shown, the fluid within balloon 25 is measured, thus allowing for the detection of higher temperatures. Specifically, considering the flow of fluid within balloon 25, it can be said that... Figure 9 The temperature measured by temperature sensor 45 in the shown state more accurately reflects the surface temperature of balloon 25. These aspects are also confirmed in the experimental results of the inventors described below.

[0112] Figure 10 This refers to the balloon catheter system 10 used in an experiment conducted to confirm the effect of stirring by the stirring device 75. In this experiment, the measured surface temperature of the balloon 25 was compared with the measured temperature of the liquid in the delivery path LP, determined based on information obtained from the temperature sensor 45. In this experiment, the balloon catheter system 10 was used... Figure 1 The balloon catheter system 10 described above is shown. However, in order to measure the temperature near the winding electrode 41, an electrode temperature sensor 81 is provided on the catheter body 20, and in order to directly measure the temperature of the surface of the balloon 25, a surface temperature sensor 82 is provided on the catheter body 20.

[0113] like Figure 11As shown, the electrode temperature sensor 81 consists of a winding electrode 41 and an electrode temperature sensor wiring 43 sandwiched between the winding electrode 41 and the inner cylinder shaft 35. The detection result of the electrode temperature sensor 81 is obtained by the temperature calculation unit 70B of the control device 70. The high-frequency energization control unit 70A receives the calculation result from the temperature calculation unit 70B and controls the high-frequency energization to the winding electrode 41 based on the information obtained from the electrode temperature sensor 81. Furthermore, Figure 10 The diagram of the temperature sensor 81 with electrodes omitted.

[0114] As surface temperature sensors 82, film-shaped T-type thermocouples (shape: approximately 5 × 15 mm, thickness: approximately 0.1 mm) are used. Four surface temperature sensors 82 are attached to the surface of the balloon using a 0.1 mm thick polyimide tape. Figure 11 As shown, four surface temperature sensors 82 are positioned at the center of the balloon 25 along the length direction LD. Furthermore, the four surface temperature sensors 82 are equally spaced around the central axis of the inner cylinder shaft 35 on the balloon 25. The four surface temperature sensors 82 are electrically connected to a high-precision temperature recorder 83 (manufacturer: HIOKI, model: LR8431), and the surface temperature is determined by the temperature recorder 83 based on the information obtained from the surface temperature sensors 82. The average value determined by the four surface temperature sensors 82 is taken as the measured value of the surface temperature of the balloon 25. Additionally, Figure 10 In the diagram, only the temperature sensors 82 on the two surfaces are shown; the remaining two are omitted.

[0115] In this experiment, an ablation treatment was performed on a pseudo-organism 99 simulating the pulmonary vein orifice of the left atrium of a human body. The pseudo-organism 99 was immersed in physiological saline solution held in a water tank 85. During the experiment, the physiological saline solution in the water tank 85 was stirred using a stirring device 86. Opposing electrodes 87, which generate high-frequency current between the electrodes 41 of the catheter body 20 and the side wall of the water tank 85, were disposed. The physiological saline solution in the water tank 85 was prepared by dissolving 0.9 wt% sodium chloride in water.

[0116] The fluid supplied from the supply device 74 to the fluid delivery path LP and balloon 25 also contains a contrast agent for X-ray imaging mixed with physiological saline solution containing 0.9 wt% sodium chloride dissolved in water. The volume of fluid injected into balloon 25 is at two levels: 10 mL and 20 mL, commonly used in actual ablation treatment. The contrast agent mixed in the fluid is Onapex (registered trademark) manufactured by Daiichi Sankyo Co., Ltd. The contrast agent is diluted at two levels: 1:2 and 1:3. Here, the dilution rate of the contrast agent means "volume of physiological saline : volume of contrast agent".

[0117] Postural testing of the distal region of the catheter body 20, including the balloon 25 being pushed towards the pseudo-organism 99. Figure 12 As shown and with Figure 6 Corresponding coaxial state Figure 13 As shown and with Figure 7 The corresponding non-coaxial state has two levels. For example... Figure 12 As shown, in a coaxial configuration, the balloon 25 is pushed from the length direction LD relative to the pseudo-organism 99, which is the target site. On the other hand, as... Figure 13 As shown, in a non-coaxial state, the balloon 25 is pushed towards the pseudo-organism 99 from a direction inclined relative to the length direction LD. In the non-coaxial state, the inner cylinder shaft 35 is bent at an angle of 30° to 45°. In the non-coaxial state, the shape of the balloon 25 does not take the outer cylinder shaft 30 and the inner cylinder shaft 35 as centrally symmetrical.

[0118] The stirring device 75 supplies and discharges the same liquid as that supplied to the liquid delivery path LP and the balloon 25 at a drive frequency of 2Hz relative to the liquid delivery path LP. The amount of liquid supplied from the stirring device 75 to the liquid delivery path LP each time and the amount of liquid discharged from the liquid delivery path LP to the stirring device 75 each time are 780 mm. 3 Furthermore, the cross-sectional area of ​​the fluid delivery path LP of the catheter body 20 is 4.76 mm². 2 On the other hand, the length DX from the distal end 30a of the outer cylinder shaft 30 to the temperature sensor 45 (refer to...) Figure 2 Set to 150mm.

[0119] If based on reference Figure 8 and Figure 9 The aforementioned tendency anticipates that the temperature variation of the liquid in the delivery path LP will reach its maximum and minimum values ​​at time intervals equal to the driving cycle of the stirring device 75. More specifically, when the stirring device 75 discharges liquid from the delivery path LP and the liquid is drawn into the delivery path LP from the balloon 25, the temperature of the heated high-temperature liquid is measured as the maximum value. Furthermore, when the stirring device 75 supplies liquid to the delivery path LP and the liquid is ejected into the delivery path LP from the balloon 25, the temperature of the low-temperature liquid remaining in the delivery path LP is measured as the minimum value. Therefore, preferably, based on the temperature variation of the liquid in the delivery path LP, the output of the temperature sensor 45 is obtained at intervals shorter than the driving cycle of the stirring device 75. In this experiment, the driving frequency of the stirring device 75 is 2Hz, so it is predicted that the temperature variation will repeatedly reach its maximum value every 0.5 seconds. Therefore, the output of the temperature sensor 45 can be measured at a time interval sufficiently short compared to 0.5 seconds, specifically at 10 millisecond intervals. That is, the liquid temperature in the liquid delivery path LP is calculated by processing information from the temperature sensor 45 at a time interval of 1 / 50 of the driving cycle of the stirring device 75.

[0120] The high-frequency energization control unit 70A of the control device 70 controls the high-frequency energization to the winding electrode 41 by setting the temperature of the liquid surrounding the winding electrode 41 to 70°C. The drive power is set to 150W.

[0121] As described above, the filling volume of liquid into balloon 25, the dilution rate of contrast agent, and the pushing method of balloon 25 were each changed at two levels, resulting in a total of eight conditions. Simulation experiments were conducted on the adaptation of the pseudo-organism 99 to the balloon catheter system 10. The temperature measurements of temperature sensor 45 at 10-millisecond intervals in each experiment were set as the temperature measurements of surface temperature sensor 82. Figures 14-21 As shown in the chart. Figures 14-21 In the chart shown, the vertical axis is set to temperature (°C), and the horizontal axis is set to the time (s) from when energizing the winding electrode 41 and the opposite electrode 87 begins. Figures 14-21 The chart shown represents the measurement results from the start of high-frequency power application until the surface temperature of the balloon 25 has stabilized sufficiently, specifically 150 to 200 seconds after the start of power application.

[0122] Figures 14-21 In the results shown, the liquid temperature in the liquid delivery path LP, as measured by temperature sensor 45, varies with a period of approximately 0.5 seconds. This temperature variation period is well integrated with the liquid supply and discharge cycle based on the 2Hz drive frequency of the stirring device 75. Furthermore, the measured value of the surface temperature of the balloon 25, as measured by surface temperature sensor 82, is approximately the same as the maximum value of the temperature variation measured by temperature sensor 45. Based on this, in the temperature calculation unit 70B of the control device 70, the maximum value (or the envelope connecting the maximum values) of the temperature variation line formed by connecting the measured values ​​of temperature sensor 45 can be determined as the surface temperature of the balloon 25. Alternatively, in the temperature calculation unit 70B of the control device 70, a triangular wave-shaped approximate curve is first determined based on the measured values ​​of temperature sensor 45, and then the maximum value (or the envelope connecting the maximum values) of this approximate temperature variation curve can be determined as the surface temperature of the balloon 25. In this way, the surface temperature of the balloon 25, which is estimated from the liquid temperature inside the outer cylinder shaft 30, has extremely high accuracy, with an error of approximately ±1°C compared to the measured value determined by the surface temperature sensor 82.

[0123] Furthermore, the temperature variation of the liquid in the delivery path LP, as measured by temperature sensor 45, is approximately 6°C to 9°C. Therefore, the temperature calculation unit 70B of the control device 70 can also determine the surface temperature of the balloon 25 by adding a specific value of 3°C to 5°C to the average value of the liquid temperature in the delivery path LP measured by temperature sensor 45. In this way, the surface temperature of the balloon 25 estimated from the liquid temperature inside the outer cylinder shaft 30 also has extremely high accuracy, with an error of approximately ±1°C compared to the measured value measured by surface temperature sensor 82.

[0124] according to Figures 14-21 The experimental results shown yielded the following findings. First, regardless of the shape of the balloon, i.e., whether it is coaxial or non-coaxial, and also regardless of the amount of liquid filling the balloon 25 or the contrast agent dilution rate of the liquid filling the balloon 25, the maximum value (or the envelope connecting the maximum values) of the liquid temperature variation in the delivery path LP measured by the temperature sensor 45 is consistent with a high accuracy of approximately ±1°C, relative to the measured value of the balloon surface temperature measured by the surface temperature sensor 82.

[0125] Second, a temperature separation of approximately 5°C occurs between the coaxial and asymmetrical states of the balloon. Specifically, when the balloon's shape is symmetrical with respect to the outer cylinder axis 30 and the inner cylinder axis 35, the liquid inside the balloon is well agitated, and the surface temperature of the balloon 25 increases. Conversely, when the balloon 25's shape is asymmetrical with respect to the outer cylinder axis 30 and the inner cylinder axis 35, the liquid inside the balloon is not sufficiently agitated, and the surface temperature of the balloon 25 does not rise. This tendency was observed regardless of the amount of liquid filled into the balloon 25 or the contrast agent dilution rate.

[0126] Regarding the amount of liquid injected into the balloon 25, if the injection volume increases from 10 ml to 20 ml, a tendency for the balloon surface temperature to decrease by approximately 2°C is observed. However, the injection volume into the balloon 25 is unaffected, and the maximum value of the liquid temperature variation in the delivery path LP measured by the temperature sensor 45 (or the envelope connecting the maximum values) is consistent with the measured value of the balloon surface temperature measured by the surface temperature sensor 82 with a high accuracy of approximately ±1°C. Similarly, the contrast agent dilution ratios of 1:2 and 1:3 are unaffected by the contrast agent dilution ratio, and the maximum value of the liquid temperature variation in the delivery path LP measured by the temperature sensor 45 (or the envelope connecting the maximum values) is consistent with the measured value of the balloon surface temperature measured by the surface temperature sensor 82 with a high accuracy of approximately ±1°C.

[0127] In summary Figures 14-21The experimental results shown show that the liquid temperature measured by temperature sensor 45 is at a minimum value corresponding to the liquid supply from the stirring device 75 to the liquid delivery path LP, and at a maximum value corresponding to the liquid discharge from the liquid delivery path LP to the stirring device 75. Furthermore, by continuously monitoring the peak value (maximum value) of the liquid temperature detected by temperature sensor 45, the surface temperature of the balloon can be accurately determined. Specifically, the balloon shape is unaffected by the amount of liquid filling into the balloon 25 or the contrast agent dilution rate, whether in a coaxial or non-coaxial state. The maximum value (or the envelope connecting the maximum values) of the liquid temperature variation in the liquid delivery path LP measured by temperature sensor 45 can be consistent with a high accuracy of approximately ±1°C, relative to the measured value of the balloon surface temperature measured by surface temperature sensor 82. Therefore, the surface temperature of the balloon 25, which is crucial during ablation treatment, can be accurately detected, displayed, and used for control.

[0128] In addition, if we summarize Figures 14-21 The experimental results shown indicate that the temperature variation of the liquid in the delivery path LP reaches its maximum and minimum values ​​within the same cycle as the driving cycle of the stirring device 75. Furthermore, the liquid temperature measured by the temperature sensor 45 reaches its minimum value corresponding to the liquid supply from the stirring device 75 to the delivery path LP, and its maximum value corresponding to the liquid discharge from the delivery path LP to the stirring device 75. Moreover, by continuously monitoring the peak value (maximum value) of the liquid temperature detected by the temperature sensor 45, the surface temperature of the balloon can be accurately determined. Specifically, the balloon shape is unaffected by the amount of liquid filling the balloon 25 or the contrast agent dilution rate, whether in a coaxial or non-coaxial state. The maximum value (or the envelope connecting the maximum values) of the liquid temperature variation within the delivery path LP measured by the temperature sensor 45 can be consistent with the measured value of the balloon surface temperature measured by the surface temperature sensor 82 with a high accuracy of approximately ±1°C. Therefore, the surface temperature of the balloon 25, which is crucial during ablation treatment, can be accurately detected, displayed, and used for control.

[0129] Furthermore, based on the above experimental results, preferably, the liquid temperature variation within the delivery path LP is monitored, and the liquid temperature is determined by obtaining detection results (information obtained by the temperature sensor 45) at time intervals less than the drive cycle of the stirring device 75. More preferably, the liquid temperature is determined by obtaining detection results from the temperature sensor 45 at time intervals less than half the drive cycle of the stirring device 75. In this case, the temperature can be detected at least once during periods when the liquid temperature in the delivery path LP decreases, and at least once during periods when the liquid temperature in the delivery path LP increases. Therefore, determining the liquid temperature by obtaining the output from the temperature sensor 45 at time intervals less than half the drive cycle of the stirring device 75 is useful for monitoring the average temperature of the liquid within the delivery path LP.

[0130] Similarly, preferably, the liquid temperature is determined by obtaining detection results from the temperature sensor 45 at intervals less than 1 / 4 of the drive cycle of the stirring device 75. In this case, the temperature can be detected at least twice during periods when the liquid temperature in the delivery path LP decreases, and at least twice during periods when the liquid temperature in the delivery path LP increases. Therefore, determining the liquid temperature by obtaining the output from the temperature sensor 45 at time intervals less than 1 / 4 of the drive cycle of the stirring device 75 is useful for understanding the profile of temperature changes in the liquid in the delivery path LP.

[0131] Furthermore, based on the maximum value of the liquid temperature variation within the liquid delivery path LP, which serves as an indicator of the surface temperature of the balloon 25, the shorter the time interval for determining the liquid temperature from the detection results obtained from the temperature sensor 45, the higher the detection accuracy. Accordingly, preferably, the time interval for determining the liquid temperature from the output of the temperature sensor 45 is set to be less than 1 / 5 of the driving cycle of the stirring device 75, more preferably less than 1 / 8 of the driving cycle of the stirring device 75, even more preferably less than 1 / 10 of the driving cycle of the stirring device 75, and even more preferably, the determination of the liquid temperature is performed continuously.

[0132] Furthermore, the "maximum value" of the liquid temperature change calculated based on the information obtained from the temperature sensor 45 refers to the temperature (°C) at which the temperature changes from rising to falling over time. Moreover, the "maximum value" is not limited to a strictly mathematical meaning and can be determined by a broken line formed by connecting temperature values ​​calculated at predetermined time intervals with a straight line, or by a continuous linear change (e.g., a triangular wave-like change) obtained by approximating temperature values ​​calculated at predetermined time intervals with a curve. Similarly, the "minimum value" of the liquid temperature change calculated based on the information obtained from the temperature sensor 45 refers to the temperature (°C) at which the temperature changes from falling to rising over time. Moreover, the "minimum value" is not limited to a strictly mathematical meaning and can be determined by a broken line formed by connecting temperature values ​​calculated at predetermined time intervals with a straight line, or by a continuous linear change (e.g., a triangular wave-like change) obtained by approximating temperature values ​​calculated at predetermined time intervals with a curve. Furthermore, the envelope connecting the maximum values ​​of temperature variations of the liquids used in this specification means, not limited to a strict mathematical sense, a line that sequentially connects the maximum values ​​of temperature variations in a broken or continuous linear form.

[0133] Hereinafter, several specific examples included in one of the above embodiments will be described. In the following description of specific examples and the accompanying drawings used in the following description of specific examples, the same reference numerals as those used for the corresponding parts of the above description are used for parts that can be constructed in the same way as described above, and repeated descriptions are omitted.

[0134] <First specific example>

[0135] (Fabrication of a balloon-equipped ablation catheter system)

[0136] A polyurethane balloon 25 with a diameter of 30 mm and a thickness of 20 µm is manufactured by blow molding a polyurethane tube. A polyurethane tube with an outer diameter of 3.6 mm, an inner diameter of 3.0 mm, and a length of 1000 mm is formed and designated as the outer tube shaft 30. In addition, a polyamide tube with an outer diameter of 1.6 mm, an inner diameter of 1.2 mm, and a length of 1100 mm is formed and designated as the inner tube shaft 35. A handle 50 is connected to the rear end (proximal end) of both the outer tube shaft 30 and the inner tube shaft 35.

[0137] A copper wire with a diameter of 0.26 mm and a length of 1700 mm, coated with an electrically insulating film made of perfluoroalkoxyalkane, is designated as wiring 42. The electrically insulating film applied to wiring 42 is peeled off by 200 mm. Starting from a position 25 mm from the end (far end) of the inner cylinder shaft 35, the wire 42 with the peeled film is coiled around the inner cylinder shaft 35, serving as a winding electrode 41 for high-frequency energization. Polyurethane tubes are fixed to the inner cylinder shaft 35 on both sides along the longitudinal direction LD, adjacent to the winding electrodes 41, by heat welding. These polyurethane tubes are designed to prevent misalignment of the winding electrodes 41 on the inner cylinder shaft 35.

[0138] A temperature sensor 45 is provided on the inner surface 10 mm from the end (far end) of the outer cylinder shaft 30. A heat shrink tube, serving as a fixing mechanism 48, is disposed on the inner cylinder shaft 35. The wire 47 of the temperature sensor 45 passes through the heat shrink tube, which is then heated on the inner cylinder shaft 35. The wire 47 is fixed to the inner cylinder shaft 35 by means of the heated and shrunken heat shrink tube. The heat-sensing part 46 of the temperature sensor 45, which is mounted on the inner cylinder shaft 35 by the fixing mechanism 48, is then separated from both the outer cylinder shaft 30 and the inner cylinder shaft 35.

[0139] The distal end of the inner cylinder shaft 35 is inserted into the balloon 25, and the rear end (proximal end) of the balloon 25 is fixed to the distal end of the outer cylinder shaft 30 by heat welding. Furthermore, the distal end of the balloon 25 is fixed to the inner cylinder shaft 35 by heat welding.

[0140] The rear end of the wiring 42, which is electrically connected to the winding electrode 41, is electrically connected to the high-frequency energized control unit 70A of the control device 70 through the liquid delivery path LP between the outer cylinder shaft 30 and the inner cylinder shaft 35 and the inside of the handle 50. Similarly, the wire 47 of the temperature sensor 45 is also electrically connected to the temperature calculation unit 70B of the control device 70 through the liquid delivery path LP and the inside of the handle 50.

[0141] The valve 58 is installed on the bifurcation of the handle 50 via the extension tube 57. A three-way stopcock valve is used as the valve 58. Furthermore, the valve 58 is connected to the stirring device 75 via the extension tube 57. Thus, the vibration applied to the liquid by the stirring device 75 is transmitted to the liquid inside the balloon 25 via the extension tube 57, the handle 50, and the liquid delivery path LP, creating a path for stirring the liquid.

[0142] (Control systems and control methods)

[0143] use Figure 10In the above-described experiment of the balloon catheter system, the information (potential) obtained by the electrode temperature sensor 81 is fed into the temperature calculation unit 70B and the high-frequency power control unit 70A of the control device 70. Based on the temperature difference of approximately 5°C between the surface temperature of the balloon 25 and the ambient temperature of the winding electrode 41, the surface temperature of the balloon 25 is controlled to 65°C. Therefore, the output of the winding electrode 41 is controlled by adjusting the application of the high-frequency voltage to the winding electrode 41, so that the liquid temperature around the winding electrode 41, determined based on the information obtained by the electrode temperature sensor 81, is 70°C. On the other hand, in the balloon catheter system 10 of the first specific example, as... Figure 22 As shown, the information (potential) obtained by the temperature sensor 45 is input to the temperature calculation unit 70B of the control device 70. In the temperature calculation unit 70B, the application of the high-frequency voltage from the high-frequency energization control unit 70A to the winding electrode 41 is adjusted, and the output of the winding electrode 41 is controlled so that the surface temperature of the balloon 25 calculated by the temperature calculation unit 70B based on the information obtained by the temperature sensor 45 is 65°C. As described above, the temperature calculation unit 70B outputs the maximum value (peak value) of the temperature variation of the liquid in the liquid delivery path LP, determined based on the information obtained by the temperature sensor 45, as the surface temperature of the balloon 25. Furthermore, Figure 22 In the balloon catheter system 10 shown, the high-frequency power control unit 70A, the temperature calculation unit 70B, and the stirring device control unit 70C are housed in a single housing. The high-frequency power control unit 70A, the temperature calculation unit 70B, and the stirring device control unit 70C may also share at least a portion of their structure (hardware).

[0144] use Figure 23 The circuit diagram shown illustrates the specific control method of the system in the first example. The AC power input is fed into the full-wave rectifier circuit via a power line filter in a manner that does not emit power noise from the high-frequency power circuit. On the other hand, a switching regulator is built in to obtain a stable DC power supply for logic circuits including the CPU and FPGA.

[0145] The current output from the full-wave rectifier circuit is converted into a higher potential DC (typically 400V~500V) by the next stage DC-DC converter. Then, it is converted into an AC square wave (typically 200KHz~3MHz frequency) by means of a high-speed chopper circuit based on MOSFET (not shown), i.e., an RF switching circuit. Through this AC conversion, the current is in a state that is harmless to humans even if it flows between the winding electrode 41 and the opposite electrode 77 of the heating element 40 through the human body.

[0146] Information from the temperature sensor 45 is transmitted via a wire 47 passing through the conduit body 20 into the temperature measurement circuit. It is then fed into a logic circuit, including a CPU and FPGA, for signal processing and control via an AD conversion circuit. Through the signal processing described below, the maximum value of the temperature variation of the liquid in the delivery path LP, determined based on the information obtained from the temperature sensor 45, and the envelope connecting these maximum values ​​are extracted. This allows for accurate detection and monitoring of the surface temperature of the balloon 25. Furthermore, the RF switching circuit is controlled so that the monitored surface temperature of the balloon 25 is always at the desired temperature.

[0147] There are various methods for extracting the envelope of the maximum temperature variation of the liquid in the delivery path LP determined based on information obtained from temperature sensor 45, but the first specific example uses... Figure 24 The method is illustrated in the flowchart. Specifically, the output from temperature sensor 45 is converted into a digital temperature signal via an AD conversion circuit at 1-millisecond intervals. The output (denoted as T) of the temperature sensor 45, digitized at 1-millisecond intervals, is recorded at its maximum value (denoted as MAX) according to the vibration cycle of the stirring device 75 (500-millisecond intervals), and used as a temperature control signal. Figure 24 In the process shown, the maximum value of the temperature control signal is the maximum value of the broken line temperature variation obtained by connecting the liquid temperature values ​​in the liquid delivery path LP, which are periodically determined based on information from the temperature sensor 45, with a straight line. This maximum value is used as the surface temperature of the balloon 25 for control.

[0148] In addition, a fail-safe protection device is adopted. The fail-safe protection device is that the current flowing between the winding electrode 41 and the opposing electrode 77 is always monitored and flows into the logic circuit including the CPU and FPGA through the resistance measurement circuit and the AD conversion circuit. When the high-frequency current is applied, if an unexpected situation occurs in the human body or during the operation, the high-frequency current is quickly cut off.

[0149] In order to make the temperature inside the balloon uniform, the operation of the stirring device 75 that vibrates and stirs the liquid through the liquid delivery path LP, the system settings, and various interfaces for the operator (surgeon) are also implemented according to signals from logic circuits including the CPU and FPGA.

[0150] Using the balloon catheter system 10 of the first specific example described above, Figure 10The experiment shown is the same as described above, using the pseudo-organism 99, water tank 85, water tank stirring device 86, opposing electrode 87, and surface temperature sensor 82. However, without using the electrode temperature sensor 81, the high-frequency energization towards the winding electrode 41 and opposing electrode 87 controls the surface temperature of the balloon 25, estimated based on the detection results of the temperature sensor 45, to 66.0°C. Other conditions for the high-frequency energization are set to 1.8MHz and the applied high-frequency power to 150W. The variation in liquid temperature within the delivery path LP, determined based on information obtained from the temperature sensor 45, and the variation in the surface temperature of the balloon 25, measured by the surface temperature sensor 82, are as follows: Figure 25 As shown in the chart. Figure 25 As shown, the maximum temperature variation of the liquid in the delivery path LP, determined based on information obtained from the temperature sensor 45, is highly consistent with the actual surface temperature of the balloon 25. Therefore, by controlling the surface temperature of the balloon 25 with high-frequency energization, the surface temperature of the balloon 25 can be made to the target value.

[0151] <Second specific example>

[0152] Next, the balloon catheter system 10 of the second specific example is as follows: Figure 26 As shown. The balloon catheter system 10 of the second specific example has an electrode temperature sensor 81 provided on the inner cylinder shaft 35. The electrode temperature sensor 81 is configured as a thermocouple with a winding electrode 41 provided on the inner cylinder shaft 35 as one electrode and a conductive wire of a different material electrically connected to the winding electrode 41 as the other electrode. In this balloon catheter system 10, based on the temperature information obtained by the electrode temperature sensor 81, the high-frequency energization control unit 70A of the control device 70 controls the high-frequency energization to the winding electrode 41. This balloon catheter system 10 also has a temperature sensor 45 disposed in the aforementioned fluid delivery path LP. Therefore, the operator (surgeon) can grasp the surface temperature of the balloon 25 as determined as described above based on the information obtained by the temperature sensor 45. The determined surface temperature of the balloon 25 can be displayed on the display unit 71 of the control device 70, and the operator can grasp the surface temperature of the balloon 25 during the operation. In addition, the display unit 71 of the control device 70 also displays the liquid temperature around the heating element 40, which is determined based on the detection results of the electrode temperature sensor 81.

[0153] The balloon catheter system 10 of the second embodiment differs from the balloon catheter system 10 of the first embodiment described above by having two temperature sensors: an electrode temperature sensor 81 and a temperature sensor 45. In the second embodiment, the surface temperature of the balloon 25, determined as described above based on information obtained from the temperature sensor 45, can be displayed on the display unit 71 of the control device 70. As the mechanism for displaying the surface temperature of the balloon 25, the second embodiment employs a digital temperature display. On the other hand, control of the output from the heating element 40 can be implemented based on the temperature value determined by the electrode temperature sensor 81. Alternatively, control of the output from the heating element 40 can also be implemented based on the temperature value determined by the sensor selected from either the electrode temperature sensor 81 or the temperature sensor 45.

[0154] In the second specific example of the balloon catheter system 10, control is achieved by using the balloon catheter system 10 to ensure that the liquid temperature around the winding electrode 41, which functions as the heating element 40, is at the desired set temperature. Therefore, the output of the heating element 40, which functions as the heating mechanism, can be directly controlled, and the maximum value and envelope of the liquid temperature variation determined based on the output of the temperature sensor 45 in the first specific example can be obtained without applying control of the ablation catheter system based on this signal. Therefore, the influence of delays caused by the signal processing time of the temperature detection circuit on the control of the balloon catheter system 10 can be eliminated, and control on the balloon catheter system 10 side can be applied.

[0155] Furthermore, in the balloon catheter system 10 of the second specific example, a display unit 71 is provided. The display unit 71 calculates the maximum value and the envelope of the temperature change of the liquid determined by the output of the temperature sensor 45, and displays it according to a digital or analog waveform, so that the surgeon can know the surface temperature of the balloon in real time.

[0156] <Third specific example>

[0157] Furthermore, the balloon catheter system 10 in the third specific example is as follows: Figure 27 As shown. In the third embodiment of the balloon catheter system 10, similarly to the first embodiment, the information obtained by the temperature sensor 45 is imported into the temperature calculation unit 70B of the control device 70. The high-frequency energization control unit 70A controls the high-frequency energization to the winding electrode 41 based on the liquid temperature determined according to the information obtained by the temperature sensor 45, and controls the output of the winding electrode 41. At this time, similar to the first embodiment, the maximum value of the liquid temperature variation determined according to the output of the temperature sensor 45 and the envelope connecting the maximum values ​​can be detected at a very fast speed, and the surface temperature of the balloon 25 can be determined with high accuracy from the temperature sensor 45.

[0158] On the other hand, in the third embodiment, similar to the second embodiment, an electrode temperature sensor 81 is provided on the inner cylinder shaft 35. The temperature calculation unit 70B of the control device 70 calculates the temperature of the liquid surrounding the winding electrode 41 based on the information obtained from the electrode temperature sensor 81. Thus, the control device 70 can monitor the occurrence of a situation where the liquid temperature, determined based on the information from the electrode temperature sensor 81, exceeds the boiling point of the liquid. When the liquid exceeds its boiling point within the bulb 25, undesirable bubbles are generated within the bulb 25. The high-frequency energizing control unit 70A of the control device 70 adjusts the high-frequency energizing toward the winding electrode 41, controlling the output of the winding electrode 41 so that no bubbles are generated within the bulb 25.

[0159] <4th specific example>

[0160] In the fourth embodiment, the balloon catheter system 10 has the same device and circuit structure as in the first embodiment. However, the method for determining the surface temperature of the balloon 25 based on information obtained from the temperature sensor 45 differs from that in the first embodiment. In the fourth embodiment, the average temperature of the liquid in the delivery path LP, determined based on information obtained from the temperature sensor 45, is calculated, and the value obtained by adding an offset value to this average value is determined as the surface temperature of the balloon 25.

[0161] According to the inventors' experimental results, the temperature variation of the liquid in the delivery path LP, as measured by temperature sensor 45, is approximately 6°C to 9°C. Therefore, the temperature calculation unit 70B of the control device 70 can determine the surface temperature of the balloon 25 as the value obtained by adding a specific value of 3°C to 5°C to the average liquid temperature in the delivery path LP measured by temperature sensor 45. Thus, the surface temperature of the balloon 25, estimated from the average liquid temperature within the outer cylinder shaft 30, also has extremely high accuracy, with an error of approximately ±1°C compared to the measured value measured by surface temperature sensor 82. Furthermore, in the fourth specific example, based on the surface temperature of the balloon 25 determined in this way, the high-frequency energization to the winding electrode 41 is adjusted, and the output from the winding electrode 41 is controlled.

[0162] The flowchart for calculating the average liquid temperature within the delivery path LP based on information from the temperature sensor 45 used in the fourth specific example is as follows: Figure 27The output of temperature sensor 45 is converted to a digital signal via an AD conversion circuit at 1-millisecond intervals, and obtained as the output (T) of the in-shaft temperature sensor. The output (T) of temperature sensor 45 is taken as a moving average every 1 second as Tav. Furthermore, the average value of the output of temperature sensor 45 has an offset of approximately -4°C relative to the maximum value of the output of temperature sensor 45, so the value obtained by adding 4°C relative to Tav is set as the surface temperature Tsu of the balloon. Other control methods are performed in the same way as in the first specific example. In addition, the flowchart method used here is only an example of calculating the average value of the liquid temperature in the liquid delivery path LP measured by temperature sensor 45.

[0163] In one embodiment described above, the balloon catheter 15 includes a balloon 25, an outer cylinder 30, an inner cylinder 35, and a heating element 40. The outer cylinder 30 is connected to the proximal end 25b of the balloon 25. The inner cylinder 35 passes through the outer cylinder 30 and extends into the balloon 25, connecting to the distal end 25a of the balloon 25. A fluid delivery path LP communicating with the inside of the balloon 25 is formed between the inner and outer cylinder 30. The heating element 40 is disposed inside the balloon 25 for heating the liquid inside the balloon 25. In this balloon catheter 15, the surface temperature of the balloon 25 is strongly correlated with the temperature within the fluid delivery path LP of the outer cylinder 30, which draws liquid from the balloon 25. In particular, the liquid temperature in the region of the fluid delivery path LP near the distal end 30a of the outer cylinder 30 is strongly correlated with the surface temperature of the balloon 25. Furthermore, in the above embodiment, a temperature sensor 45 is provided between the outer cylinder shaft 30 and the inner cylinder shaft 35 to obtain information related to the temperature within the delivery path LP. The surface temperature of the balloon 25 is strongly correlated with the temperature of the liquid flowing into the delivery path LP from the balloon 25; therefore, based on the information obtained by the temperature sensor 45 within the delivery path LP, the surface temperature of the balloon 25 can be detected with high precision. This significantly improves the ablation treatment effect using the balloon catheter 15. Moreover, unlike the balloon 25, which undergoes large deformation due to expansion and contraction, the temperature sensor 45 can be stably maintained within the delivery path LP by means of the outer cylinder shaft 30 and the inner cylinder shaft 35.

[0164] In one specific example of the above-described embodiment, the length along the longitudinal direction LD from the distal end 30a of the outer cylinder shaft 30 to the temperature sensor 45 is 5 mm to 150 mm. According to this specific example, when repeatedly ejecting liquid from the liquid delivery path LP into the balloon 25 and drawing liquid from the balloon 25 into the liquid delivery path LP, liquid inside the balloon 25, especially liquid near the surface of the balloon 25, can be drawn into the outer cylinder shaft 30, and the surface temperature of the balloon 25 can be evaluated with high accuracy based on the temperature sensor 45 inside the outer cylinder shaft 30.

[0165] In one specific embodiment described above, the temperature sensor 45 is mounted on the inner cylinder shaft 35, which is movable relative to the outer cylinder shaft 30. When the inner cylinder shaft 35 is moved distally relative to the outer cylinder shaft 30 and the balloon 25 is extended, the temperature sensor 45 is also located within the liquid delivery path LP between the outer cylinder shaft 30 and the inner cylinder shaft 35. According to this specific embodiment, the temperature sensor 45 can be located within the liquid delivery path LP between the outer cylinder shaft 30 and the inner cylinder shaft 35 regardless of the relative position of the inner cylinder shaft 35 relative to the outer cylinder shaft 30. Therefore, the temperature sensor 45 can be stably protected by means of the outer cylinder shaft 30, regardless of the relative position of the inner cylinder shaft 35 relative to the outer cylinder shaft 30.

[0166] In one specific embodiment described above, the temperature sensor 45 may also be mounted on the outer cylinder shaft 30. According to this embodiment, the temperature sensor 45 is located within the outer cylinder shaft 30 regardless of the relative position of the inner cylinder shaft 35 relative to the outer cylinder shaft 30. Therefore, the temperature sensor 45 can be stably protected by the outer cylinder shaft 30 regardless of the relative position of the inner cylinder shaft 35 relative to the outer cylinder shaft 30.

[0167] In one specific example of the above-described embodiment, the temperature sensor 45 includes a heat-sensing part 46 and a wire 47 connected to the heat-sensing part 46. The wire 47 is fixed to the inner cylinder shaft 35 or the outer cylinder shaft 30, and the heat-sensing part 46 is separated from both the inner cylinder shaft 35 and the outer cylinder shaft 30. According to this specific example, the temperature sensor 45 can be mounted on the inner cylinder shaft 35 or the outer cylinder shaft 30 via the wire 47. On the other hand, the heat-sensing part 46 is kept in a non-contact state from the inner cylinder shaft 35 and the outer cylinder shaft 30, which have large heat capacity, so the temperature of the liquid in the liquid delivery path LP can be measured with high accuracy and speed.

[0168] In one specific example of the above-described embodiment, the control device 70 first determines the temperature variation of the liquid in the delivery path LP based on information obtained from the temperature sensor 45, and then determines the surface temperature of the temperature sensor 45 based on the determined temperature variation. According to this specific example, as demonstrated in the above-described experiment, the surface temperature of the balloon 25 can be detected with high precision, thereby improving the effectiveness of ablation therapy.

[0169] In one specific example of the above-described embodiment, the control device 70 first determines the temperature variation of the liquid in the delivery path LP based on information obtained from the temperature sensor 45, and then determines the maximum value of the determined temperature variation as the surface temperature of the balloon 25. According to this specific example, as demonstrated in the above-described experiment, the surface temperature of the balloon 25 can be detected with high precision, thereby improving the effectiveness of ablation therapy.

[0170] In one specific embodiment described above, the balloon catheter system 10 includes a stirring device 75 that repeatedly supplies liquid to and discharges it from the delivery path LP at a constant cycle. The control device 70 obtains information from the temperature sensor 45 and performs calculations at time intervals less than the constant cycle. According to this specific example, as demonstrated in the above experiments, the surface temperature of the balloon 25 can be detected with high precision, thereby improving the effectiveness of ablation therapy.

[0171] In one specific embodiment of the above-described embodiment, the balloon catheter system 10 includes a stirring device 75, which repeatedly supplies a predetermined amount of liquid to and discharges it from the delivery path LP. The length (mm) from the distal end 30a of the outer cylinder shaft 30 to the temperature sensor 45 along the longitudinal direction LD is the predetermined amount (mm) of liquid supplied to and discharged from the delivery path LP. 3 Divide by the cross-sectional area of ​​the above-mentioned liquid delivery path (mm²) 2 The obtained values ​​are as follows. According to this specific example, by repeatedly ejecting liquid into the balloon 25 via the liquid delivery path LP and drawing liquid from the balloon 25, liquid near the surface of the balloon 25 can be introduced to the vicinity of the temperature sensor 45 inside the outer cylinder shaft 30. Therefore, the surface temperature of the balloon 25 can be evaluated with high precision using the temperature sensor 45 inside the outer cylinder shaft 30.

[0172] In one specific embodiment described above, a wiring 42 electrically connected to the heating element 40 and the control device 70 is provided, and the temperature sensor 45 includes a wire 47 electrically connected to the control device 70. The inner cylinder shaft 35 is movable relative to the outer cylinder shaft 30. Both the wiring 42 and the wire 47 are mounted on the same side of the outer cylinder shaft 30 and the inner cylinder shaft 35, extending within the liquid delivery path LP. According to this specific embodiment, when the inner cylinder shaft 35 and the outer cylinder shaft 30 move relative to each other, the wiring 42 and the wire 47, both extending within the liquid delivery path LP, can be effectively prevented from tangling. As a result, the liquid temperature inside the balloon 25 based on the heating element 40 can be stably regulated, and the surface temperature of the balloon 25 can be stably controlled.

[0173] In one embodiment described above, the balloon catheter 15 includes a balloon 25, an outer cylinder 30, an inner cylinder 35, and a winding electrode 41. The outer cylinder 30 is connected to the proximal end 25b of the balloon 25. The inner cylinder 35 passes through the outer cylinder 30 and extends into the balloon 25, connecting to the distal end 25a of the balloon 25, forming a fluid delivery path LP identical to that within the balloon 25. The winding electrode 41 is disposed within the balloon 25 and is energized at a high frequency to apply a high-frequency current to the fluid within the balloon 25, thereby heating the fluid. According to this embodiment, the fluid can be heated by applying a high-frequency current. Furthermore, the temperature sensor 45 is shielded from the high-frequency current, allowing for high-precision detection of the temperature of the fluid within the balloon 25, thereby improving the effectiveness of ablation therapy.

[0174] One embodiment has been described through a number of examples, but these examples are not intended to limit the embodiment. The above embodiment can be implemented in a wide variety of other examples, and various omissions, substitutions, changes, additions, etc., can be made without departing from its spirit.

[0175] For example, in one embodiment described above, a liquid delivery path LP is provided between the outer cylinder shaft 30 and the inner cylinder shaft 35. Liquid is supplied to and discharged from the balloon 25 via this single liquid delivery path LP. However, this is not limited to this example; two or more liquid delivery paths LP may be provided between the outer cylinder shaft 30 and the inner cylinder shaft 35. In this variation, the two or more liquid delivery paths LP may also include a supply liquid delivery path for supplying liquid to the balloon 25 and a discharge liquid delivery path for discharging liquid from the balloon 25. In this variation, the surface temperature of the balloon 25 can also be accurately monitored using a temperature sensor 45 disposed within the discharge liquid delivery path.

[0176] Industrial availability

[0177] This invention relates to a balloon catheter system and balloon catheter for the treatment of arrhythmias such as atrial fibrillation, endometritis, cancer, etc.

[0178] Explanation of reference numerals in the attached figures

[0179] 10…Balloon catheter system, 15…Balloon catheter, 25…Balloon, 25a…Distal end, 25b…Proximal end, 30…Outer cylinder shaft, 35…Inner cylinder shaft, 40…Heating component, 41…Winding electrode, 42…Wiring, 45…Temperature sensor, 46…Heat sensing part, 47…Wire, 70…Control device, 75…Stirring device, LD…Length direction, LP…Liquid delivery path, DX…Length.

Claims

1. A balloon catheter system, characterized in that, Equipped with a balloon catheter, control device, and stirring device. The aforementioned balloon catheter includes a balloon, an outer tube shaft, an inner tube shaft, a heating element, and a temperature sensor. The aforementioned outer cylinder shaft is connected to the proximal end of the aforementioned balloon. The aforementioned inner cylinder shaft passes through the aforementioned outer cylinder shaft and extends into the aforementioned balloon to connect with the distal end of the aforementioned balloon. The aforementioned heating element is disposed inside the aforementioned balloon and is used to heat the liquid inside the aforementioned balloon. The aforementioned temperature sensor is disposed in the liquid delivery path, which is formed between the aforementioned outer cylinder shaft and the aforementioned inner cylinder shaft and communicates with the aforementioned balloon. The aforementioned control device is electrically connected to the aforementioned temperature sensor, and determines the surface temperature of the aforementioned balloon based on the output of the aforementioned temperature sensor. The aforementioned stirring device repeatedly supplies the aforementioned liquid into the aforementioned liquid delivery path and discharges it from the aforementioned liquid delivery path at a constant cycle. The aforementioned control device first determines the temperature variation of the aforementioned liquid in the aforementioned liquid delivery path based on the output of the aforementioned temperature sensor, and then determines the maximum value of the aforementioned temperature variation as the aforementioned surface temperature of the aforementioned balloon.

2. The balloon catheter system as described in claim 1, characterized in that, The length from the far end of the aforementioned outer cylinder shaft to the aforementioned temperature sensor along the longitudinal direction is more than 5 mm and less than 150 mm.

3. The balloon catheter system as described in claim 1 or 2, characterized in that, The aforementioned temperature sensor is installed on the aforementioned inner cylinder shaft. The aforementioned inner cylinder shaft can move relative to the aforementioned outer cylinder shaft. When the inner cylinder shaft moves relative to the outer cylinder shaft on the axially distal side and the balloon is extended, the temperature sensor is located in the liquid delivery path between the outer cylinder shaft and the inner cylinder shaft.

4. The balloon catheter system as described in claim 1 or 2, characterized in that, The aforementioned temperature sensor is mounted on the aforementioned outer cylinder shaft.

5. The balloon catheter system as described in claim 1 or 2, characterized in that, The aforementioned temperature sensor includes a heat-sensing element and a wire connected to the aforementioned heat-sensing element. The aforementioned wire is fixed to the aforementioned inner cylinder shaft or the aforementioned outer cylinder shaft, and the aforementioned heat-sensing part is separated from the aforementioned inner cylinder shaft and the aforementioned outer cylinder shaft.

6. The balloon catheter system as described in claim 1 or 2, characterized in that, The aforementioned control device obtains output from the aforementioned temperature sensor at intervals shorter than the aforementioned constant period.

7. The balloon catheter system as described in claim 1 or 2, characterized in that, The aforementioned stirring device repeatedly supplies a predetermined amount of the aforementioned liquid into and out of the aforementioned liquid delivery path. The length (mm) from the distal end of the aforementioned outer cylinder shaft to the aforementioned temperature sensor along the longitudinal direction is the aforementioned predetermined quantity (mm). 3 Divide by the cross-sectional area of ​​the aforementioned liquid delivery path (mm²) 2 The values ​​obtained are as follows.

8. The balloon catheter system as described in claim 1 or 2, characterized in that, The device is equipped with wiring that is electrically connected to the aforementioned heating element and the aforementioned control device. The aforementioned temperature sensor includes a wire that is electrically connected to the aforementioned control device. The aforementioned inner cylinder shaft can move relative to the aforementioned outer cylinder shaft. The aforementioned wiring and the aforementioned conductor are both installed on the same side of the aforementioned outer cylinder shaft and the aforementioned inner cylinder shaft, and extend within the aforementioned liquid delivery path.

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